ML20151X078
| ML20151X078 | |
| Person / Time | |
|---|---|
| Issue date: | 08/21/1998 |
| From: | Charles Brown NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Chappell C NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| References | |
| NUDOCS 9809160246 | |
| Download: ML20151X078 (9) | |
Text
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August 21, 1998 MEMORANDUM FOR:
Ross Chappell, Chief l
Package Certification Section, SFPO FROM:
Christopher Brown, Materials Engineer Package Certification Section, SFPO l
SUBJECT:
MEETING
SUMMARY
CONCERNING THE GNS-16 l
TRANSPORTATION CASK APPROVAL TO TRANSPORT ALUMINUM-CLAD MTR SPENT FUEL WITH EXPOSED FUEL MEAT Attendees:
NELC D_QE EDLOW GNS GERMANY David Tiktinsky Tracey Mustin Marty Ebert B. Beine Nancy Osgood Chuck Messick (Via conference call)
Bernie White Li Yang Chris Brown Ross Chappell William F. Kane Introduction A meeting was held at the request of the Department of Energy at Rockville, Maryland, on July 2,1998, concerning the transportation of Aluminum-clad MTR-type Spent Fuel with exposed fuel meat in the GNS-16 cask. The meeting agenda, provided by DOE, is attached.
Discussion l
1.
DOE discussed their definition of failed MTR-type spent fuel. In addition, the history and current condition of the failed MTR-type spent fuel was discussed.
2.
DOE presented a brief talk on the oxidation rate of uranium vs. the oxidation rate of uranium aluminide.
3.
The staff requested information concerning the rate of oxidation of the uranium in the failed fuel meat. The staff also wanted to know more about the oxidation of the uranium in the fuel meat;in particular, information on the amount of particulates that could be released from the failed fuel meat.
4.
DOE indicated that the cladding of the Brazilian fuel had corrosion pitting and that ff the fuel meat was exposed in some places. DOE indicated that video records l
were available from which the area of exposed fuel meat could be estimated.
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1-5.
GNS stated that the fuel cladding which is damaged greater than hairline cracks and l
pin hole leaks was not covered (i.e., authorized) by the German Certificate.
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The staff indicated that the review of the application would proceed; but that a containment evaluation of failed fuel would be needed. The staff indicated this could possibly be a " bounding" type analysis.
7.
GNS indicated they would perform a containment evaluation considering failed fuel.
Attachments: Meeting Handouts Distribution:
NRC FC NMSS r/f NRC PDR SFPO r/f Attendees w/o Attachment WFKane MWHodges To receive a copy of this document, indicate in the box: "C" - Copy without attachment / enclosure "E" = copy with attachment / enclosure "N" = No copy OFC SFPO SFPO, h SFPO CLBro9rkdDHT$hinsky CRChell NAME 8/)i/9b 8h98 8/2//98 LDATE OFFICIAL RECORD COPY
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u Topics For a Meeting for the DOE Office of Spent Fuel L
Management at the NRC Spent Fuel Project Office
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Regarding GNS-16 Transportation Cask Validation TO l
Transport Aluminum-clad MTR-type Spent Fuel With Cladding Penetrations July 2,1998 BACKGROUND BRAZIL MTR-Type FUEL ASSESSMENTS
- DOE /WSRC fuel assessment, July 1996
- Final Appendix A data for IEA-R1 fuel for the 1998 shipment
- Trip report for Brazil facility assessment DOE DEFINITION OF " FAILED" FOR MTR-Type FUEL
- Unique behavior of breached aluminum clad (with exposed fuel meat) per DOE National Spent Fuel Program repon from DOE-INEEL
- SRTC fuel material studies (Natraj Iyer/ Bob Sindelar at 803-725-2695)
- Summary of evolution in DOE technical paper preser.ted at PATRAM 98 DOE TESTS AND ASSURANCES OF FUEL CONDITION
- Appendix B requirements for content cenifications and sip test procedure prior to DOE shipment authorization SOUTH AMERICAN SHIPMENT GNS-16 TRANSPORT CASK VALIDATION STATUS
- Edlow/NCS to address their responses to NRC technical comments
- Discuss all safety concerns of transponing breached-clad Brazilian fuel VALIDATION OF GNS-16 CASK S URGENT
- NRC recommendation by 7/15, DOT cenificate needed by 7/19 to load fuel PATH FORWARD
- Improving DOE / DOT /NRC coordination in FRR shipment plannint through bi-weekly conference calls
- DOE provide to NRC staff relevant DOE documents to facilitate application reviews for MTR and TRIGA research reactor fuel shipments
- DOE to continue plans for improvement in cask utilization and contract execution l
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THE REQUIREMENTS FOR CANNING FOREIGN RESEARCH iy d
REACTOR SPENT NUCLEAR FUEL
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Pomibilities and focal polonim
'tive shipment routes, and specir '
1ent. The DOE TRANSCOM C D. Massey (1). C E Me.ssick m. B. K Chambers (2). K A. Chacey (3) i j
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(1) Sandia National Laboratories, Albuquerque,NM, United States
'i itified during the presentance.
(2) U.S. DOE, Savannah River Site, Aiken, SC, United States (3) U.S. DOE, Washington, DC, United States
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SUMMARY
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a0 in accordance with the RecordofDecision on a Nuclear Weapons Nonproliferation Policy J
Concerning Foreign Research Reactor Spent Nuclear Fuel (DOE,1996a), the U.S.
Depa tment of Energy (DOE) is implementing a 13-year program under which DOE V'
accepts foreign research reactor spent nuclear fuel (SNF) containing uranium that was k
l Commission (before 1972) or the Nuclear Regulatory Commission (after 19 g
enriched in the United States, and whose export was licensed by the Atomic Energy i
c is of vtuying age and condition. The transportation to and storage of the SNF st the DOE's
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receiving sites may sequire special packaging for some of this spent research reactor fuel.
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In response to a number ofissues associated with the transportation of damaged fuel, the L
DOE has developed packaging criteria for transportation and storage of research reactor V
spent nuclear fuel and defined " failed" for those purposes. The criteria incorporate a clear p
understanding of the unique characteristics of research reactor fuel, as well as the technical c;
and regulstory issues associated with safe storage and transport.
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! Introduction i
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'c Beginning in the 1950s, as part of the " Atoms for Peace" program, the United States provided 7
nuclear technology to foreign nations for peaceful applications in exchange for their promise to l forego development of nuclear weapons. A major element of this program was the provision h.? -
of research reactor technology and the highly enriched uranium (HEU) needed in the early
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years to fuel the research reactors in the past, after irradiation in the research reactor, the 4 spent nuclear fuel was returned to the United States so that the United Stater maintained control over disposition of the HEU that it provided to other nations. The United States j
accepted foreign research reactor spent nuclear fuel until the "Off Site Fuels Policy" expired in 1988 for HEU fuel and 1992 for low enriched uranium (LEU) fuel.
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i On May 13,1996, the U.S. Department of Energy issued a Recoraf ofDecisron on Nacien s;nce only mechanically sound spent nuclear fuel elements are shipped, no radioactwe r
Weapont NorproInferation Policy Concerning Foreign Reseach Reactor Spent Nuclear releases ne expected during transit. To ensure no such releases, the spent fuel elements Fuel (DOE,1996e). The goal of the long-term policy is to recover ennched urannan are checked prior to shipment to identify and separase any damaged fuel elements. The exported from the Usuced States, while giving foreign research reactor (FRR) operators damaged fuel elements are then encapsulseed and prepared for shipment." (DOE,1996b) sufficient time to develop their own long-tenn solutions for storage and disposal of spent i
fuel. The spent nuclear fuel (SNF) accepeed by the U.S. DOE under the policy must be out As draAed, the definition of " failed fuel" could be interpreted to regture encapsulation of of the research reactors by May 13,2006 and returned to the U.S. by May 12,2009.
any spent fuel whose extemal cladding, in any way. "has cracked, pitted, conoded or posentially allows the leakage of radioactive rnetenal." Such an overbroad interpretation Forty.one countnes are eligible for shipment of their SNF. The total inventory of eligible could lead to the encapsulation of spent fuel that would otherwise not be required for either fuel contains approximately 17,000 Matenals Testing Reactor (MTR)-type SNF assemblies transportation or storage, as was the case in the development of the WSRC cntena.
and approximately 5,000 Trammg, Research, Isotope, General Atomic (TRIGA)-type SNF elements. The SNF will be packaged in shipping casks at the site oforigin and transported The Prelissinery Crieerie to one of two DOE receiving sites. For MTR-type fuel, the receiving site will be the Savannah River Site (SRS) in Aiken, Son % Carolina. For TRIGA fuel, the receiving site la response to the absence of clear a,_* ' y guedance or technical standards for cannmg will be the Idaho National Engineering andi.nvuonmental laboratory (INEEL). All SNF MTR-type fuel which has matenal conditions such as through.cled pitting, the WSRC will be transported dry in U.S. Nuclear Regulatory Commission (NRC) licensed or andertook an effort to develop standards 'oy which MTR-type spent fuel would bejudged Department of Transportation (DOT) cestified casks. The MTR fuel will be initially stored for purposes of cannmg prior to transport. The effort focused strongly on potential cannmg I
under water at existing wet storage facilities at SRS. The TRIGA fuel will be stored dry requuements for intene storage because transport issues were felt to be DOE or NRC upon receipt at the INEEL Irradiated Fuel Storage Facility.
cask-related issues.
I Much of the FRR spent fuel which will be accepted by the DOE has been stored for long The original SRS storage criteria was based on having no exposed fuel meat nom any form f
penods of time (10 to 30 years)in facilities not designed for long-term seorage. The ofcladding penetration on a fuel plate. In response to DOE's request for SRS fuel receipt.
detenoraison ofsome of the spent fuel in storage required that the DOE develop acceptance l
cntena for ---+--+ of aluminum-based foreign research reactor spent nuclear fuel, criteria for the transportation and storage of the spent fuel, especially in light of the WSRC ' formed DOE on December 31,1996 that studies showed that corrosion nodules m
numbers of assemblics to be accepted under the new policy. In response, the two receiving on the surface of a fuel plate would not penetrate the clad unless the diameter of the nodule f
sites, INEEL and SRS, developed interim entens for packagmg spent nuclear fuel based on exceeded approximately 1/g inch diameter. The WSRC criteria w_a.ad that any fuel i
the statements in the Ennrensierwaf1syser 9asenernt (ES) on a T,.,
JNuclear assembly that did not meet this criteria be considered failed and be encapsulated prior to
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1 'egent Nonprofferation Policy Concermng Foreign Research Reactor Spent Nucless-ducct storage at SRS. Radionuclide sampling (sip test) was added to build a technical Furl (DOE,1996b).
database to support future decisions on encapsulation, shipping requirements, and storage at SRS. Although the WSRC
.....-A4 criteria were not formally approved bf the j
As the first site to receive spent nuclear fuel under the new acceptance policy SRS duected DOE, they became the conservative basis until an oflicial DOE fuel==paa-criteria j
I could be issued.
i its operstmg contractor, the W1 Savannah River Company (WSRC), to develop is,-.;
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la early 1997 conservative criteria were applied to Italian, Spanish, German, and Swiss i
line Eavireemental lampeet Statement fuel. Several fuel assemblies did not meet the.m,,;
4e criteria as a result of nodules
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greater than 1/4 inch, leading to the assumption of through-clad pitting. Can design t
The EIS defines " failed" SNF broadly, and does not differentsate how that term should be sequuements were identified and some cans were fabncated. One of the assemblies i
interpreted for purposes of transportation or storage. In fact, some SNF that is techacally identified as failing the WSRC cntens was a CIEMAT-owned MTR fuel assembly in
" failed" for purposes of reactor operation snow pose no (or very little) risk of fission ssorage at Dounresy. The assembly was found to have several corrosion nodules greater
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product release and, therefore, may be tmnsported and stored safely without any additional than 1/4 inch on fuel plates. Even though the cask owner, the shipper, and relevant j
packaging. The glossary defined " failed fuel" as "SNF whose extemal cladding has competent authorities agreed that the assembly could be shipped within all transportation cracked, pitted, corroded, or potentially allows the leakage of radioactive material." The requirements, DOE decided that, in light of the only existing criteria, they could not accept
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EIS also states in an appendix that addresses storage issues that:
the " failed" fuel assembly unless it was canned. News of the characterization of the
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anembly as " failed" because of the corrosion nodules spread quickly and initiated an intense effort by DOE to address this issue.
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Technical Consideratians of Reseerek Renesar Fuel Characteristics low. Release rates on the onder of 10 viCi (10 x 10* Ci) per hour per 0.5 square inch of exposed fuel were measured.
l The situation in Dounreay and the recosmtion that the interun canning criteria being used could have a large impact on transport costs and storage with no heahh or safety benefits The findings in Brazil agree with the data gathered at the SRS whsch show that the
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concerned DOE. As a result, it was deemed appropriate to clarify the criteria for behavior of the UAl,-AI, U,0 -Al, or U, Sin-Al fuel " ment" used for the MTR fuel is such 3
p transportation and storage of rese9rch reactor SNF, including what constitutes " failed" SNF shot the conosion rates are extremr:y low, less than 0.001 inch (25 microns) per year in for those purposes. The clarificatson was needed twe==a the nuclear industry normally water with good chemical control against corrosion. The very low corrosion rate of the interprets reactor failed fuel as fuel which is no longer - --
" t for use in the reactor.
fuel men' exposed to water actually approaches that of the alumimen cladding itself. In a However, fuel that is no longer satable for use in a reactor may be perfectly acceptable for dry envuonment there is essentially no corrosion (Sindelar,1997). Because transportation safe transportation and storage. Hence, the use of the word " failed" in the context of an of the SNF to Savannah River will take place in a dry condition, it is expected that fission operational failure.
product release rates durmg transportation will be vntually zero and, essentially, unmeasurable.
Reactor failed fuel assemblies are typically identified during reactor operation when off-i gas activities increase above normal levels, usually as a resuk of leakage of radioactive TRIGA fuel has a design that physically resembles that ofcommercial light water reactor insteric_Is from a damaged elemene(s). There are several teclunques available to identify as (LWR) fuel, but there is a very significant difference in the metallurgical properties of the i
individual " leaking" assembly, and usually it is removed som the reactor and placed into two types. TRIGA fuel consists of a stack of three 6-inch cylindncal slugs of U-ZrH, clad i
the spent fuel pool. AAer removal of a "leaksng" MTR assembly or TRIGA element from with either an aluminum alloy or stainless steel. In the case of aluminum cladding, a the reactor, the le=Irare of radioactive snatenals normally stops. The assembly or element breach of the cladding can resuh in accelerated corrosion of the cladding due to the p
no longer leaks because the fission product release mechemsen resuhang from the heat and galvaruc couple between the fuel and the clad. In the case of stainless steel cladding, this l
fission created durms enticality is no longer present.
type of salvanic' coupling and accelerseed corrosion damage is not observed. However, in
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either case the fuel matrix matenal is protected by the formation of a very tough and almost
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Because the accepted definition of reactor failed fuel applies to the performance of fuel impermeable ZrO layer that forms on the surface of the fuel matnx that is in contact with 3
dunng reactor operation and implies release of fission products during reactor operation, the water. Thus, for the TRIGA fue), the fissile material (and, hence, the fission pmducts) reactor failed fuel was deemed an inappropnase term to use for the present considerations are unlikely to escape from the fuel rnstrix. This resuhs in a very low release rate of of transportation and storage. A more appmpriate approach to the problem would be to fission peducts. Data on TRIGA fuel fission product release have been obtained at up to j
define " acceptability" with respect to SNF behavior under the environmental conditions 800*C, and measurable fission product release did not occur until the ts...r..ac reached
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present during transportation and storage. The definition of " acceptability" depends 350=C, at winch the overall fractional release gaseous fission products was uly 10
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principally on three factors: (1) fuel condation, (2) transportation (per DOT and NRC virtually negligible (Richards,1977 and Mathews,1997). Release ofnon-gaseous fission regulatsons), and (3) receipt and storage at SRS or INEEL products would be even less.
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Research Reseter Fuel Characteristles Which lefhsesee Breached Claddheg Given that the corrosion ra*es (hence, activity release rates) are very low for research p,,g.,,,,,,
reactor fuel, acceptance criteria that assume conosion-related activity release will be a j
controlling mechanism would not be particularly relevant. Additionally, encapsulation An MTR fuel assembly has an UAl.- AI, U 0. -Al, or U Si -Al fuel matrix that is clad with may be detrimental m pmper nunagement of SNWut has cWg perha%ue m 3
3 3 an ahtninum alloy. TRIGA fuel r.,nsists ofa U-ZrH, fuel matrix that is clad with either corrosion or mechanical damage. Whether at INEEL or SRS, SNF received m a canned cluminum or stainless steel (in some cases,incoley). The design of the fuel matrix condition will be uncanned prior to storage so that the operating contractor at these sites strongly influences fission product release if the cladding is breached. In the case of the can observe the d con &6on & M In h caw Gp,p @M h, F
MTR fuel, the fissile material is tightly bound in the aluminum fuel matrix and, hence' the mmsim rates of perfwated fuel are bener eW mammng m #
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fission products are " captured" in this metal (aluminum) fuel matrix. With this type or chemistry than by placing fuel in another container. Because the condition ofcanned fuel design, perforation of the cladding, the resuk of mechamcal damage or localized corrossen cannot be visually ascertained, the degradation rate of canned fuel, in fact, would be j
such as pitting, has little effect on the release of fission pmducts outside of reactor unknown. In addition, the chemical environment inside a scaled can cannot be easily l
operations. Recent inspections ofcladding damaged MTR fuel in Brazil that had been in l
determined or controlled. In the case of TRIGA fuel, which will be shipped and stored dry, wet storage for over 20 years, has shown that the release rate of fission products is very the uly rease fw canning defected fuel wmld be e prevent vdeWe Hssim @ cts fmni
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being released dunng shipping. However, as discussed above, volatile fission products are l
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above, there are good reasons for not cannmg cladding-performacd SNF. The most anportant of these is that chemistry consol (pH, conductivity) is the primary vanable in When the issue is structwal damage, there are signiGcant differences between MTR md comroHing conesion em would lead to fission product release. SNF stored in sealed cans TRIGA fuel. In either case it is very important that the SNF be able to be manipulated e am glow miequese A..a., control.
(picked up, moved, etc.) without danger ofloss of structural imegrity, i.e., the SNF will not l
fall apart during handling and shipping. Criticality control configwation is also an The Final Acceptance Criteria nnportant issue. The MTR fuel elements maatain excellent structural integrity, even with many small cladding breaches. However,in the case of the aluminum clad TRIGA fuel, a h for accephng fuel in an "as is" condition for transportation and storage are number of fuel pins with minimal visible corrosion have actually broken apart. Hence,
@mly. Transportmion entena might,in certam cases, be less stringent than TRIGA fuel that has broken or otherwise lost its structural meegrity needs to be transported storage criteria at a given facility given the temporary duration of transport and the in baskets that allow for easy handling and containment of the fuel within configwations
%r ness of the transport package. Unless there is a specific reason why these two criteria a
analyzed in the safety analyses. 'Ihe transportation ofTRIGA fuel and similar LWR fuel 2
- vrerent, however, shipping across vanous states should be done under as slugs, in damaged structural configwansons, has already been accomplished using baskets coalitions as storege in any given state facility.
ef 250-mesh screen. A minor modification of these baskets for a particular cask type may be necessary but it is not an obstacle or safety issue.
Based upon me foregoing reasons, spent nuclear fuel that does not comply with all of the followmg criteria will be considered " failed" for the transportation / storage functions ami Cask vendors under contract to DOC to provide transportation service to the Foreign wiH require special handhng prior to being transported to and stored in a DOE facility.
Research Reactor Spent Nuclear Fuel A-;~ Program were asked to supply informa-tion related to the design of their particular cask (s), the status of each cask license and/or T.4c. ruum comply wie an shipping cask license and/or certificate of e
certificase orcompliance (COC), and any cask i,-...- r-applicable to transportation of SNF'with cladding penetrations or other damage. In all cases, the transportation of SNF cornpliance conditions.
SNF nmn be unictwdly sound, i.e., not change shape with handling.
e with perforated cladding was within the cask safety analyses. While cask representatives SNF nmn not be bem or deformed such the the SNF cannot be positioned in the casli.
indicated that some form of additional cask certificasson would be required, none believed 4
that diere would be any difficulty in obtaining the required certificaten.
Fuel whose history and origin cannot be traced must be adequately packaged with regent to shippmg to meet the necessary enecality prevention entens for unknowns Under suspect The controlling SNF storage issue for wet storage is the ability of the pool clearv.sp systems conditions, se shipper and die eventurd receiwr (INEEL or SRS) rney requite that the to maintain water activity below authonzed limits. SRS has evaluated the cacability of the shippmg facility do testing (under y.ds approved by the receiving facility) to prove basins [ Receiving Basin for Offsite Fuels (RBOF) and L Area Spent Fuel Sk., ige Basin] to g,,,,,,,g g, y,,t cope with SNF that has defects that are greater than those which simply make the fuel e myiable for use in a reactor (Sindelar,1997). Release rate calculations, based on a The Ensi accepe_-
criteria is based on verifying the structural integrity of the SNF and breached clad reference fuel
.." *y containing a bounding fission product inventory, insunng &H SNF the has been damaged with respect to this criteria is suitably packaged were compared to actual measured fission product release rates from a corroded (with for slupment and handling. As has been discussed above, corrosion related fission pmduct cladding penetration) Brazilian MTR fuel element for verification. Calculations were release is not significant except as it sney affect basin water cleanup at SRS; however, even made of activity 1 uildups in both RBOF and L Area basins assuming that approximate'l in this case, the expected (and verified) rates of fission product releases are so low as to 10% (1,500 memblies) of all of the SNF that will be received is perforated, that all o(the make a limitmion based on this criterion unp===y. It is clear that structwal integrity is perforated SNF has damage and release rates similar to the Brazilian fuel, and that these have fission product inventories equivalent to the referenced fuel assembly. Dunns nonnel
-die key *m operation of either basin the increase in activity from the perforated SNF is of no Accordingly, a set of hflR -,
e criteria based on an assurm, e of structural integrity a,.w..a. For the situation in which the pool cleanup system finils, the activity buildup for handling and criticality control and a check (or verification based on site records) of in either pool is very slow, allowmg months to years of time to correct the situation expected fission product release in wet storage is appropnate.
without concern for exceeding pool water quality / release limits (Sindelar,1997)
For the case ofTRIGA fuel, additional.,.. ---- related to the special nature of the Based on the data presented and discussions with SRS personnel,it was concluded that wet design are e since expenence has shown the there are certain external storage of conoded (with cladding penetration) MTR fuel should not be the basis for
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indicators" ofpotential intemal degradation that would lead to str bndhnt could result in breakage of the fuel assembly must be plac for shipping. He exact container design will need to be defined for e type (the 250-mesh screen enclosure would appear to be a ne decision to package TRIGA to ensure safe handling will tests, inspections, and measurements.
CONCLUSION He spent nuclear fuel acceptance criteria developed by DOE address transporting damaged fuel. The criteria recognize the characteristics of (C
fuel and properly distinguish between fuel conditions under reactor op
!,.- e transport conditions.
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REFERENCES 4
.s.
p.-.d DOE,1996a, Record ofDecision for the Final Environmental Impact St i
Proposed Nuclear Weapons Nonproliferation Policy Concerning Fo Jl-Nuclear Fuel. May 1996, U.S. Department ofEnergy.
DOE,1996b, DOE /EIS-0218F, February 1996. Environmental Impact S
!j Proposed Nuclear Weapons Nonproliferation Policy Conceming Fore Spent NuclearFuel.
i I
7 9
Richards, W. J., " Failed Fuel Task CORE Term Meeting," Memor 1
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McClellan AFB, CA to W. L. Hurt, th0TCO.
a Mathews, T. A.," Fuel Packaging Criteria for Research Reactor TRIG 97." 7/18/97. Memo to E. J. Ziem!anski.
a Sindelar and J.P. Howell,"P.adioactivity Release from Aluminum Base i
Fuel in Basin Storage," WSRC TR 97-0153, May 30,1997, a
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UNITED STATES j
j NUCLEAR REGULATORY COMMISSION 2
WASHING?ON, D.C. 20066-4001
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g August. 21, 1998 MEMORANDUM FOR:
Ross Chappoil, Chief Package Certification Section, SFPO FROM:
Christopher Brown, Materials Engineer Package Certification Section, SFPO
SUBJECT:
MEETING
SUMMARY
CONCERNING THE GNS-16 TRANSPORTATION CASK APPROVAL TO TRANSPORT ALUMINUM-CLAD MTR SPENT FUEL WITH EXPOSED FUEL MEAT Attendees:
HEC QQE EDLOW GNS GERMANY David Tiktinsky Tracey Mustin Marty Ebert B. Beine Nancy Osgood Chuck Messick (Via conference call)
Bernie White Li Yang Chris Brown Ross Chappell William F. Kane introduction A meeting was held at the request of the Department of Energy at Rockville, Maryland, on July 2,1938, concerning the transportation of Aluminum-clad MTR-type Spent Fuel with exposed fuel meat in the GNS-16 cask. The meeting agenda, provided by DOE, is attached.
Discussion 1.
DOE discussed their definition of failed MTR-type spent fuel. In addition, the history and current condition of the failed MTR-type spent fuel was discussed.
2.
DOE presented a brief talk on the oxidation rate of uranium vs. the oxidation rate of uranium aluminide.
3.
The staff requested information concerning the rate of oxidation of the uranium in the failed fuei meat. The staff also wanted to know more about the oxidation of the uranium in the fuel meat;in particular, information on the amount of particulates that could be released from the failed fuel meat.
4.
DOE indicated that the cladd!ng of the Brazilian fuel had corrosion pitting and that the fuel meat was exposed in some places. DOE indicated that video records were available from which the area of exposed fuel meat could be estimated.
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. 5.
GNS stated that the fuel cladding which is damaged greater than hairline cracks and pin hole leaks was not covered (i.e., authorized) by the German Certificate.
6.
The staff indicated that the review of the application would proceed; but that a containment evaluation of failed fuel would be needed. The staff indicated this could possibly be a " bounding" type analysis.
7.
GNS indicated they would perform a containment evaluation considering failed fuel.
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Attechments: Meeting Handouts I
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Topics For a Meeting for the DOE Office of Spent Fuel Managernent at the NRC Spent Fuel Project Office Regarding GNS-16 Transportation Cask Validation To Transport Aluminum-clad MTR-type Spent Fuel With Cladding Penetrations July 2,1998 BACKGROUND BRAZIL MTR-Type FUEL ASSESSMENTS
- DOE /WSRC fuel assessment, July 1996
- Final Appendix A data for IEA-R1 fuel for the 1998 shipment
- Trip report for Brazil facility assessment j
DOE DEFINITION OF " FAILED" FOR MTR-Type FUEL
- Unique behavior of breached aluminum clad (with exposed fuel meat) per DOE National Spent Fuel Program report from DOE-INEEL
- SRTC fuel material studies (Natraj Iyer/ Bob Sindelar at 803-725-2695)
- Summary of evolution in DOE technical paper presented at PATRAM 98 DOE TESTS AND ASSURANCES OF FUEL CONDITION
- Appendix B requirements for content certifications and sip test procedure prior to DOE shipment authorization SOUTH AMERICAN SHIPMENT GNS-16 TRANSPORT CASK VALIDATION STATUS
- Edlow/NCS to address their responses to NRC technical comments
- Discuss all safety concerns of transporting breached-clad Brazilian fuel VALIDATION OF GNS-16 CASK IS URGENT
- NRC recommendation by 7/15, DOT certificate needed by 7/19 to load fuel PATH FORWARD
- Improving DOE / DOT /NRC coordination in FRR shipment planning through bi-weekly conference calls
- DOE provide to NRC staff relevant DOE documents to facilitate application reviews l
for MTR and TRIGA research reactor fuel shipments
- DOE to continue plans for improvement in cask utilization and contract execution l
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THE REQUIREMENTS FOR CANNING FOREIGN RESEARCH
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REACTOR SPENT NUCLEAR FUEL i
i ponsibilities and focalpoint is k stive shipenent mnes, and specir. '
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, eat. Tbe DOE TRANSCOM C D. Massey (1), C E Messick m B. K Chambers M. K A. Chacey (3) g (1) Sandia National Laboratories, Albuquerque, NM, United States I;
1tified during the presentanon (2) U.S. DOE, Savannah River Site, Aiken, SC, United States (3) U.S. DOE, Washington, DC, United States i>
SUMMARY
in accordance with the Record ofDecision on a Nuclear Weapons Nonpro!fercrion Policy k
Concerning Foreign Research Reactor Spent Nuclear Fuel (DOE,1996a), the U.S.
Department of Energy (DOE) is implementing a 13-year program under which DOE a:cepts foreign research reactor spent nuclear fuel (SNF) containing uranium that was l enriched in the United States, and whose export was licensed by the Atomic Energy g
Commission (before 1972) or the Nuclear Regulatory Commission (after 1972). The SNF is of varying age and condition. The transportation to and storage of the SNF at the DOE's receiving sites may require special packaging for some of this spent research reactor fuel.
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In response to a number ofissues associated with the transportation of damaged fuel, the DOE has developed packaging criteria for transportation and storage ofresearch reactor n
spent nuclear fuel and defined " failed" for those purposes. The criteria incorporate a clear v
understanding of the unique characteristics of research reactor fuel, as well as the technical E..
2 and regulatory issues associated with safe storage and transport.
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! Introduction i
I Begimiing in the 1950s, as part of the " Atoms for Peact" program, the United States provided y
nuclear technology to foreign nations for peaceful applications in exchange for their promise to i
l forego development of nuclear weapons. A major element of this program was the provision d
of research reactor technology and the highly enriched uranium (HEU) needed in the early
,3_-
years to fuel the research reactors. In the past, after irradiation in the research reactor, the 4 spent nuclear fuel was retumed to the United States so that the United States maintained 2-control over disposition of the HEU that it provided to other nations. The United States
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accepted foreign research reactor spent nuclear fuel until the "Off Site Fuels Policy" expired in 1988 for HEU fuel and 1992 for low enriched uranium (LEU) fuel.
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On May 13,1996, the US. Departinent of Energy i===I a RecordofDecision on Nuclear s,,c sy.cch,,icany soused spent ancher Asel eleinesses are shipped, iso radioactive l
Wegens Nonprohferation Policy C.-e.. Foreign Research ReactorSpent Nuclear releases are expected during transit. To ensure no such releases, she spent fuel elemenes
[
Furt (DOE,1996a). The goal of the long-term policy is to recover enriched urannen are checked prior to shipment to identify and separase any damaged fuel elements. The exported froen the United States, while giving foreign research reactor (FRR) opersoors damaged fisel elements are then encapsulseed and prepared for shipment." (DOE,1996b) l sufficient time to develop their own long-term solutions for suorage and desposal of spent Asel. The spent nuclear fuel (SNF) accepted by the US. DOE under the policy must be out As drafted, the derwution of " failed fuel" could be interpreted to requwe encapsdation of of the research reactors by May 13,2006 and returned to the US. by May 12,2009.
say spent fuel whose external claddag, in any way. "has cracked, pitted, conoded or pasentially allows the leakage of radioactive snasenal." Such an overbread interpretation Forty.cne countnes are eligible for shipment of their SNF. The total L..
4mi ofeligible could lead to the encapsulation of spent fuel that would otherwise not be required for either fuel contams approximately 17,000 Masenals Testing Reactor (MTR)-type SNF assembhes waasportatson or storage, as was the case in the development of the WSRC criteria.
2 and approximately 5,000 Tramang, Research, Isotope, General Atomic (TRIGA)-type SNF elements. The SNF will be packaged in shipping casks at the site oforigin and transponed The Prelissinary Crieeria to one of two DOE receiving sites. For MTR-type fuel, the receiving site will be the Savannah River Site (SRS) in Aiken, South Carolina. For TRIGA fuel, the receiving site la response to the absence of clear regulatory guidance or techmcal standards for canning will be the Idaho Natsonal Engmeering and Envuonmental Laborneory (INEEL). All SNF MTR-type fuel wiuch has mecenal comhtsons such as through-clad pretmg, the WSRC l
will be transported dry in US. Nuclear Regulatory Commission (NRC) hcensed or andertook an effort to develop standards by which MTR-type spent fuel would bejudged Department of Transportation (DOT) certified casks. The MTR fuel will be initially scored for purposes of cannmg prior to transport. The effort focused serongly on potential cannrng under water at existing wet storage facilities at SRS. The TRIGA fuel will be stored dry mparements for intenm suorage because tramport issues were felt to be DOE or NRC
+
upon receipt at the INEEL Irr-t=ame Fuel Storage Facility.
cak.velated issues.
j Much of the FRR spent fuel whsch will be accepeed by the DOE has been stored for long The origmal SRS storage entens was based on having no exposed fuel mest from any form t
penods of time (10 to 30 years) in facilities not designed for long-term storage. The ofcladding penetration on a fuel plate. In response to DOE's request for SRS fuel receipt detenoration of some of the spent fuel in storage reqmred that the DOE develop acceptance I
cneens for acceptance of aluminum-based foreign research reactor spent nuclear fuel, i
criteria for the transportation and storage of the spent fuel, especially in light of the WSRC informed DOE on December 31,1996 that studies showed that corrosion nodules numbers ofassemblics to be accepted under the new policy. In response, the two receiving on the surface of a fuel plate would not perrtrase the clad unless the diameter of the nodule sites, INEEL and SRS, developed intenm entena for packagmg spent nuclear fuel based on exceeded approximately 1/8 inch diameter. The WSRC criteria recommended that any fuel the statements in the Environsernsallagnact Shwesernt (E25) on a 1",,,, a.'Naselear assembly that did not meet this entene be considered failed and be encapsulated prior to Fegens Norgrohferation Policy Concernisqr Foreign Research Reacsor.Tpent Nuclear duett storage at SRS. Radionuclide sampling (sip test) was added to build a technical Furl (DOE,1996b).
deshase to support future decisions on encapsulation, shipping requirements, and storage at SRS. Although the WSRC-recommended entens were not formally approved bf the As the first site to receive spent nuclear fuel under the new acceptance policy, SRS dwected DOE, they became the conservative basis until an official DOE fuel acceptance criteria i
its operating contractor, the W- ^ J - _ Savannah River Company (WSRC), to develop I
could be issued inspection and m a criteria.
a i
la early 1997 conservative criteria were applied to Italian, Spanish, German, and Swiss The Environmental Inspect Statesseet fuel. Sewral fuel assemblies did not meet the acceptance criteria as a result of nodules i
gresser than I/4 inch, leading to the assumption of through. clad pitting. Can design The EIS defines " failed" SNF broadly, and does not differentinse how that term should be sequnements were identified and some cans were fabncated. One of the assemblies irnerpreted for purposes of transportation or storage. In fact, some SNF that is technscally identified as failing the WSRC cntena was a CIEMAT-owned MTR fuel assembly in
" failed" for purposes of reactor operation may pose no (or very little) risk of fission isorage at Dounreay. The assembly was found to have,everal corrosion nodules greater j
product release and, therefore, may be transponed and stored safely without any additional than 1/4 inch on fuel plates. Even though the cask or,ner, the shipper, and relevant i
packaging. The glossary defined " failed fuel" as "SNF whose external claddmg has
= A,a authorities agreed that the assembly cot /d be shipped within all transportation cracked, pitted, corroded, or potentially allows the leakage of radioactive marerial." The seguirements, DOE decided that, in light of the o'Jy existing criteria, they could not accept l
EIS also states in an appendix that addresses storage issues that.
ihe " failed" fuel assembly unless it was canned News of the characterization of the usembly as failed" because of the corrosion modules spread quickly and initiated an santase effort by DOE to address this issue.
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l Technical Cacenderations of Research Reseter Feel Characteristics low. Release ruees on the order of 10 stCi (10 x 10* Ci) per hour per 0.5 square inch of l
exposed fuel were measured.
l The situation in Dounreay and the recosmtson that the interim canning entens being used i
could have a large impact on transport costs and storage with no heakh or safety benefits The findings in Brazil agree with the data gathered at the SRS which show that the
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i concerned DOE. As a result, it was deemed appropnase to clarify the criteria for behavior of the UAI,-AI, U,0 -AI, or U,Si,-Al fuel " ment" used for the MTR fuel is such 3
transportation and storage of research reactor SNF, inchsdeng what constitutes " failed" SNF ihat the conoscon rates are e.. 4 low, less than 0.001 inch (25 microns) per year in j
for those purposes. The clarification was needed twe==e the nuclear industry ownnally water with good chemical control agamst conosson. The very low corrosion rate of the interprets reactor failed fuel as fuel which is no longer -- - 2 for use in the reactor fuel mest exposed to water actually approaches that of the ahuninum cladding itself. In a r
However, fuel that is no longer samtable for use in a reactor may be perfectly acceptable for dry envuonment there is essentially no corrosson (Sindelar,1997). Because transportation safe transportation and sacrage. Hence, the use of the word " failed" in the context of an of the SNF to Savannah River will take place in a dry condition, it is expected that fission operassonal failure.
product release races dunng transportation will be vetually zero and, essentially, unmeasurable Reactor failed fuel assemblies are typecally identified durmg reactor operation when off-i gas activities increase above nonnel levels, usually as a resuk of leakage of radioactive TRIGA fuel has a design that physically resembles that ofcommercial light water reactor l
materials from a damaged element (s). There are several ' " _,- - available to k.ntify an (LWR) fuel, but there is a very significant difference in the snetallurgical properties of the individual" leaking
- assembly, and usually it is removed from the renesor and plad ineo two types. TRIGA fuel consists of a stack of three 6-inch cylindncal slugs of U-ZrH, clad the spent fuel pool. After removal of a "leakag" MTR assembly or TRIGA element from with either an aluminum alloy or stamless seeet in the case of alurninum cladding, a l
the reactor, the leakage of rachoactive masenals nonnelly scope. The assembly or element breach of the claddmg can result in accelerated conosion of the cladding due to the no longer leaks because the fissson product release n=rimism resulting from the heat and galvanic couple between the fuel and the clad. In the case of stainless steel cladding, this fission created dunng criticality is no longer present.
type of galvanic' coupling and accelerseed conoseon damage is not observed However, in either case the fuel matrix masenal is protected by the formation of a very tough and almost
[
Because the accepted definition of renceor failed fuel applies to the performance of fuel anpermeable ZrO, layer that forms on the surface of the fuel matrix that is in contact with dunng reactor operation and implies release of fission products dunns reactor operation, the water. Thus, for the TRIGA fuet, the fissile maserial (and, hence, the fission products) reactor failed fuel was deemed an inappropnaec term to use for the present considerations are unlikely to escape frorn the fuel matrix. This results in a very low release race of cf transportation and storage. A more appropnate approach to the problem would be to lission products. Data on TRIGA fiael fission product release have been obtained at up to define " acceptability" with respect to SNF behavior under the envuonmental conditions 800"C, and measurable fission product release did not occur until the t...,~..a e reached present during transportation and storage. The definition of" acceptability" depends 350*C, at which the overall fractional release gaseous fission products was only 10 4
principally on three factors: (1) fuel cc "r -. (2) transportation (per DOT and NRC virtually negligible (Richards,1977 and Mathews,1997). Release ofnon-gaseous fission j
regulatsons), and (3) receipt and storage at SRS or INEEL products would be even less.
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l Research Reactor Feel Charnesedstics Which lefinence Breached r= - --
Performance
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Given that the corrosion rates (hence, activity release rates) are very low for research l
l reactor fuel,-
x criteria that assume corrosion-related activity release will be a
[
controlling mechanism would not be particularly relevant. Additionally, encapsulation An MTR fuel assembly has an UAl,-Al, U,0, -Al, or U,Si -Al fuel matrix that is clad with may be detrimental to proper management of SNF that has cladding perforations due to i
3 l
an aluminum alloy. TRIGA fuel consists of a U-ZrH, fuel matrix that is clad with either conosion or mechanical damage Whether at INEEL or SRS, SNF received in a canned i
clummum or stainless steel (in some cases,Incoley). The design of the fuel matrix condition will be uncanned prior to storage so that the operatirig contractor at these sites strongly influences fission product release if the cladding is breached. In the case of the can observe the real condition of the fuel. In the case of SNF shipped to Savannah River, MTR fuel, the fissile material is tightly bound in the aluminum fuel matrix and, hence, die a
conosson rates of perforated fuel are better controlled by maintaining proper pool fission pn> ducts are " captured
- in this metal (aluminum) fuel matrix. With this type of chemistry than by placing fuel in another container. Because the condition ofcanned fuel f
design, perforsten of the cladding, the result of mechanical damage or kicalized corrosion cannot be visually.m.;
. :, the degradation rate of canned fuel, in fact, would be such as pitting, has little effect on the release of fission products outside of reactor unknown. In addition, the chemical environment inside a sealed can cannot be easily operations. Recent ia===e*4== ofcladding damaged MTR fuel in Brazil that had been in l
determined or controlled. In the case of TRIGA fuel, which will be shipped and stored dry, wet storage for over 20 years, has shown that the release ruee of fiss:en products is very the only reason for canning defected fuel would be to prevent volatile fission products from j
being released dunng shipping. However, as discussed above, volatile fission products are
[
I 1
1212 1213 i
not released by the TRIGA fuel matrix until attainment of temperstwes well above those
~
determming if canning (in a sealed container) should be required. In fact, as discussed associated with typcal and accidemal transport conditions and storage operations.
above, there are good reasons for not canning cladding-perforated SNF. The most important of these is that A...a;., control (pH, conductivity)is the primary variable in l
When the issue is structwat damage, there are significant differences between MTR and cowrolling corrosion &m would lead to fission poduct release. SNF stored in sealed cans TRIGA fuel. In either case it is very important that the SNF be able to be manipule'.ed h am allow adequase cheminry control.
(picked up, moved, etc ) without danger cf loss of structural integrity, i.e., the SN; will not fall apart durmg handing and shipping. Criticality control configemtion is also an The Final Acceptance Crteerie important issue. The l> fTR fuel elements masntain excellent sin.ctwal integrity, even with l
many small cI=ldmg b esches. However,in the case of the ahaninum clad TRIGA fuel, a Criteria for acceptmg fuel in an "as is' condition for ;.--.,~.1_
and storage are j
number of fuel pins with minnnel visible corrosion have actually broken apart. Hence, considered joimly. Transportmion criteria might, in certam cases, be less stringent than TRIGA fuel that has brtci or otherwise lost its structwal integrity needs to be transpawd storage criteria e a given facility given the temporary duration of transport and the
[
in baskets that allow for eng handling and containment of the fuel within configuratens soliusuies: of the transport package. Unless there is a specific reason why these two critens j
analyzed in the safety analyses. The transportation ofTRIGA fuel and similar LWR niel shodd be differem, however, shippng across vanous states should be done under as slugs,12 damaged structwal configwatsons, has already been accomplished insing baskets sinngem conditions as storage in any given state f.cility.
l ef 230-mesh screen. A mintw modification of these baskets for a particular cask type may 5,4 necessary but it is not an obstacle or safety issue.
j Based upon the foregoing reasons, spent nuclear feel that does not comply with all of the i
followmg critena will be considered " failed" for the transportation /seorage fations and l
Ccsk vendors ve der contract to DOE to provide ;._,~.;
. service to the Foreign win require special handling prior to being transported to sad stored in a DOE facility-L Research kcactor Spent Nuclear Fuel A ;- Program were asked to supply informa-t ti9n related to the design of their particular cask (s), the status ofeach cask license and/or Tmnsportmoon must comply wie au shipping cask license an&or certificate of e
certificate of compliance (COC), and any cask requirements applicable to transportatiou of SNF'with cladding penetrations or other damage. In all cases, the transportation of SNF compliance conditions.
SNF nmst be unicturaHy sound,i.e., not change shape with handling.
e with performeed cladding was within the cask safety analyses. While cask.w..;.;ives SNF rnest mit be lies or defonned such that the SNF cannot be positioned in ihm.
e indicated that some form of additional cask certification weinld be re.pired, none believed thu there would be any difficulty in ciAsining the requued certification.
Fuel whose himary and origin cannot be traced must be #-_,
' packaged with regard to j
shippmg to meet the necessary cnticality prevention entens for unknowns. Under suspect T1:e controlling SNF storage issue for wet storage is the ability of the pool cleanup systems conditions, the shipper and the eventual receiver (INEEL or SRS) may requae that the to maintain water activity below av.horized limits. SRS has evaluated the capability of the shipping facility do testing (under pecedures appoved by the receiving facility) to prove basins [ Receiving Basin for Offsite Fuels (RBOF) and L Area Spem Fuel Storage Basin] to g,,,,, or g, rueg, cope with SNF that has defects that are greater than those which simply make the fuel wmeptable for use in a reactor (Sindelar,1997). Release rate calculations, based on a The final acceptance criteria is based on verifying the structwal integnty of the SNF and bruched clad reference fuel assembly containing a bounding fission product inventory,
- ,,,,
- ag the SNF that has been damaged with respect to this criteria is suitably packaged 4
were compared to actual measured fission product release rates from a corroded (with cladding penetration) Brazihan MTR fuel element for verification. Calculations were for shipnem and handling. As has licen discussed above, corrosion related fission pmduct release is not significant except as it may affect basin water cleanup at SRS; however, even made of activity buildups in both RBOF and L Area basins assuming that approximately in &is cueAe expected (and verified) rates of fission pmduct releases are so low as to 10% (1,500 assemblies) of all of the SNF that will be received is perforated, that all of the snake a limitatio i based on this criterion unnecessary. It is clear that structural integrity is perforated SNF has damage and release rates similar to the Brazilian fuel, and that these have fission product inventories equivalent to the referenced fuel assembly. Dunns normal
' he key issue.
operation of either basin the increase in activity from the performeed SNF is of no Accordingly, a set of MTR acceg ance criteria liased on an assurance of structural integnty co.+a. For the situation in wluch the pool cleanup system fails, the activity buildup for handling and criticality control and a check (or verification based on site records) of in citi r pool is very slow, allowmg months to years of time to correct the situmma without concern for exceeding pool water quality / release limits (Sindelar,1997).
expected fission product release in wet storage is appropriate.
For the case of TRIGA fuel, additional. _
=- n related to the special nature of the Based on the data,,.-.a and discu,sions with SRS personnel, it was eencluded that wet design are appopnete since expenence has shown that there are certain external storage cf corroded (with claddag penetration) MTR fuel shou'd not be the basis for
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l r"esultant breakage during handling. TRIGA 1214 indicators" of potential intemal degradation that would lead to s handhny could result in breakage of the fuel assembly must be pl for shipping. The exact container design will need to be dermed for e type (the 250-mesh screen enclosure would appear to be applicable The decision to package TRIGA to ensure safe handling wil i
tests, inspections, and measurements.
~ - - - -
CONCLUSION The spent nuclear fuel acceptance criteria developed by DOE addres transporting damaged fuel. The criteria recognize 6e characteristics of re
~ ~frj fuel and properly distmguish between fuel conditions under reactor o 7 e ~ wa tr"insport Conditions.
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REFERENCES
.5 g.2 DOE,1996a, Record of Decision for the Final Environmental Impact S 1
Proposed Nuclear Weapons Nonproliferation Policy Conceiaing For Nuclear Fuel. May 1996, U.S. Department ofEnergy
^
DOE,1996b, DOE /EIS-0218F, February 1996. Environmental Impact St Proposed Nuclear Wespons Nonproliferation Policy Concerning Fo Spent Nuclear Fuel.
Richards, W. J., " Failed Fuel Task CORE Team Meeting," L.emora McClellan AFB, CA to W. L. Hurt, LMITCO.
Mathews, T. A.," Fuel Packaging Criteria for Research Reactor TRIG 97," 7/18/97, Memo to E. J. Ziemianski.
Sindelar and J.P. Howell,"Radicactivity Release from Aluminum-Based Fuel in Basin Storage," WSRC TR 97 0!$3, May 30,1997.
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